244 Annals of the Carnegie Museum. 



Head 3.29-3.25 in length to end of lateral line; depth 1.8-2.2; 

 D. 16-18, usually 17, counting everything; A. 28-31, of which the 

 first is minute and the third very large; serrse 26-28; interorbital 

 2-2.23 in the head; eye 4.5-5.5 in the head; origin of dorsal equidistant 

 from tip of snout and end of lateral line; space between dorsal and 

 caudal fulcra equal to the base of the dorsal or a little longer, equal 

 to the head less the opercle or shorter; second suborbital in the adult 

 in contact with the pre-opercle, leaving a naked border at the angle 

 in the younger specimens; depth of caudal peduncle 2.5-2.75 in length 

 of head in the smaller specimen, 3.33 in the larger; adult with a faint 

 humeral spot, otherwise without spots; young with the sides profusely 

 spotted. Caudal margined with dark, its base with a V-shaped dark 

 area; in the smallest from Lagoa de Paranagua, there is a dark band 

 on the end of the caudal peduncle. 



Very similar to Serrasalmo macidatus, but without traces of teeth 

 on the palate, the snout shorter, the interorbital wider, the serrae 

 fewer. 



8. Rooseveltiella altus (Gill). (Plate XLVI.) 



Pygocentrus alius Gill, Proc. Acad. Nat. Sci. Phila., 1870, p. 93 (Maranon or 

 Napo River); Eigenmann & Eigenmann, Proc. U. S. Nat. Mus., Vol. XIV, 

 1891, p. 80; Eigenmann & Ogle, Proc. U. S. Nat. Mus., Vol. XXXIII, 1907, p. 

 35 (Napo or Maranon); Eigenmann, Reports Princeton Univ. Exp. Patagonia, 

 Vol. Ill, 1910, p. 442. 



Distribution. — Maraiion basin. 



D. 17; A. 33; depth .8; head 2.75; snout obtuse, less than diameter 

 of eye, which is 4.5-5 in the head; interorbital 2.2 in the head; a 

 narrow naked area between suborbital and pre-opercle; fourteen 

 teeth in each jaw; origin of dorsal nearer base of upper caudal rays 

 than eye, its height about half the length of the head; origin of anal 

 under last half of dorsal; pectorals scarcely to ventrals; gill-rakers 

 pointed, a little less than half the length of eye; twenty-six abdominal 

 serrae. Grayish iridescent, tinged with bluish; sides with traces of 

 very hazy round spots; dorsal spotted; anal and caudal dusky; scales 

 34-90-37. 



Known only from the type in the U. S. National Museum, No. 

 21432. Collected by Orton in the Napo or the Maranon, for a photo- 

 graph of which I am indebted to the authorities of the United States 

 National Museum. {Cf. Plate XLVI.) 



